题目：请实现一个函数，把字符串中的每个空格替换成”%20“。例如输入”We are happy."，则输出“We%20are%20happy."。
1 void replaceBlank(char string[], int length) 2 {//length为string的总容量 3 if (string == NULL && length <= 0) 4 return ; 5 int oriLength = 0; 6 int numberOfBlank = 0; 7 int i = 0; 8 while (string[i]!=' ') 9 { 10 oriLength++; 11 if (string[i++]==' ') 12 numberOfBlank++; 13 } 14 /*newLength 为把空格替换成'%20'之后的长度*/ 15 int newLength = oriLength + 3*numberOfBlank; 16 if (newLength > length) 17 return; 18 int indexOfOriginal = oriLength; 19 int indexOfNew = newLength; 20 while (indexOfOriginal >= 0 && indexOfNew > indexOfOriginal) 21 { 22 if (string[indexOfOriginal]!=' ') 23 { 24 string[indexOfNew--] = string[indexOfOriginal--]; 25 } 26 else 27 { 28 indexOfOriginal--; 29 string[indexOfNew--] = '0'; 30 string[indexOfNew--] = '2'; 31 string[indexOfNew--] = '%'; 32 } 33 } 34 }